Hundreds of fish dead in Kent lake after aquatic pesticide treatment; WA Ecology and WSDA investigating

I live in The Lakes neighborhood in Kent. The Lakes neighborhood is a part of the Green River Natural Resources area, which is a major 304-acre protected wildlife sanctuary for many species of fish and fowl including bald eagles. The lakes in the Lakes neighborhood are private, man-made lakes which also share water with the Green River (occasionally we see river otters and beavers from the Green River in and around the lake).

The Lakes neighborhood is managed by an HOA and the HOA contracts out maintenance of the neighborhood lakes. Last week, one of the HOA’s contractors performed an aquatic treatment on the Main Lake using Hydrothol 191. The lakes are fairly shallow (they are around 4-8 feet deep at most).

Within 48-36 hours, myself and other residents documented a major fish mortality event involving large numbers of fish throughout the main lake.

Multiple government agencies are now involved. We have had visits from City of Kent personnel, the EPA, the Washington State Department of Ecology Spill Response Team, and the Washington State Department of Agriculture. Ecology is investigating under ERTS #749529, and WSDA has an open pesticide complaint under #T26002407.

It has been about 5 days since the fish kill. At this point, the hundreds of carcasses are now decomposing and the smell is extremely strong in parts of the neighborhood.

What has made this situation especially concerning is that residents have received different explanations from HOA leadership and contractors about what happened to cause the mass fish kill.

Some residents were told that low dissolved oxygen caused the fish deaths. Others were told malfunctioning aerators contributed to the problem. Residents have also been told that killing large amounts of algae or vegetation can itself reduce dissolved oxygen as organic material decomposes. Because the fish deaths happened so temporally close to the Hydrothol 191 treatment, myself and other residents understandably want investigators to determine whether the treatment contributed directly, indirectly, or not at all.

We are trying to figure out whether all permit/label requirements were followed, what caused the fish kill, how other wildlife who frequent the lake will be impacted, and who is responsible for removing the carcasses and remediating the lake.

The part that concerns many of us residents the most is that this is no longer just a disagreement between residents and an HOA. State and local agencies have physically responded and investigations are underway, but we are still struggling to get clear answers about what happened, how this will impact local wildlife, who knew what, what chemicals were applied, and who is responsible for fixing it.

If you work in aquatic ecology, fisheries, pesticide regulation, environmental law or regulation, investigative journalism, HOA law, environmental enforcement, or Washington state/local government (especially if you have experience with Ecology, WSDA, EPA, or aquatic pesticide permits), my neighbors and I would greatly appreciate advice.

Specifically, we’d like to know what records we should request, what agencies or elected officials we should be contacting, and what steps residents can take to ensure the investigation addresses both the immediate fish kill and the broader contractor/HOA oversight issues.

I have extensive photos and video documenting the fish mortality, decomposing carcasses, wildlife interacting with the dead fish, and the Department of Ecology’s on-site response.

If you have relevant expertise but would rather not comment publicly, please DM me.

Also posted in r/SeattleWA. Posting here as well because I’m specifically hoping to reach Seattle-area environmental professionals, journalists, attorneys, regulators, and others familiar with Washington environmental enforcement.